Hi folks,

Had my a4 2 years and I've always had 245 width tyres on the car and though they look great and give the boring estate a meaner look they're also more expensive. I do mostly dual-carriageways and long sweeping B roads, so demands for better performance and hard breaking isn't as important as longevity and cost.

 

245/40 18 is what I have now, so could i stick 225/40 on the car or is it necessary to go up on the profile?

 

Conflicting information on the internet with some claiming it's fine and others saying increasing profile is a must. I have no clue what the J factor is of my alloys (8j maybe), all I know is they're twin 5 spokes, picture for reference. Thinking of cross climates, lots of miles per year in every weather condition.

Hello Marta,

Simple question first:- 

Is your cheaper 225/40 listed as a variant on the tyre pressure chat on the inside of the fuel flap, or wherever? 
If not, I would forget it. Fitting non standard tyres on the vehicle may invalidate your insurance in the event of a claim - if nothing else. 
The narrower width will of course reduce the rolling dia. of wheel + tyre, ( for the same profile) and could result in gearing issues etc. I could work out the difference for, but I guess you can do that yourself. 
If it were mine, I would be searching out the most competitive prices for the correct 245 width. 
Perhaps you can let us know how you get on with the best price Marta

Kind regards,

Gareth. 

An option on the door is a 225/45 which I guess makes sense?

Difference between 245 and a 225 is £40 per tyre which is ridiculous and it’s just not worth it to me. Might double check with my local audi and give an answer once I’ve fitted some new shoes.

So you cannot compare the prices of 245/40 with 225/40, since  225/40 is not an optional fit. 
You quite understandably need to compare 245/40 price with 225/45. 
It really is as simple as that.

As you are finding, prices are influenced by volume manufacturing demands for sizes. 
Perhaps you could keep us.updated Marta.